Inking apparatus with multi-positioning capability

ABSTRACT

An inking apparatus including an inking head which is manually adjustable in the X, Y and Z directions to facilitate quick and easy positioning of an inking probe in proximity to a defective die on a semiconductor wafer to ink and mark the die for exclusion from further processing. A horizontal positioning plate is horizontally adjustably mounted on a base plate, and an angular adjustment arm is angularly adjustably mounted on the horizontal positioning plate. The inking head is vertically adjustably mounted on the end of the angular adjustment arm and carries an ink reservoir from which ink is dispensed through an inking probe to the dies on the wafer.

FIELD OF THE INVENTION

[0001] The present invention relates to devices used in the testing andinking of dies fabricated on a semiconductor wafer substrate. Moreparticularly, the present invention relates to an inking apparatus whichhas multi-positioning and adjusting capability in the inking ofmultiple, disparately-located defective dies on a semiconductor wafersubstrate.

BACKGROUND OF THE INVENTION

[0002] A conventional method used by the semiconductor industry in themanufacturing of semiconductor integrated circuits includes the steps offabrication, wafer sort, assembly and test, respectively. In thefabrication step, as many as several thousand dies (integrated circuits)are formed onto a semiconductor wafer. In the wafer sort step, each ofthe dies on the wafer is tested to determine its electricalcharacteristics and operability, and defective dies are distinguishedfrom operable dies. The defective dies are often marked by an ink markat the wafer sorting step. In the assembly step, the unmarked, operabledies are assembled into a package, and in the test step, the packagedintegrated circuits are tested for operability and reliability.

[0003] At the wafer sort step, the dies are tested to establish whichdies on the wafer function properly. Each die is tested to allfunctional product specifications for both DC and AC parameters. Fourtesting objectives are pursued: (1) chip functionality, in which allchip functions are tested to ensure that only fully-functional chips areassembled and packaged in subsequent steps; (2) chip sorting, in whichchips are separated or sorted on the basis of their operating speedperformance under various voltage and timing conditions; (3) fab yieldresponse, which yields important information that may lead toimprovements in the overall fabrication process; and (4) test coverage,in which high test coverage of the internal device nodes is achieved atthe lowest possible cost. The wafer sort procedure is similar to thein-line parametric test except that every die on the wafer is tested, inmany cases using the same automated test equipment (ATE). Furthermore,the wafer sort procedure is usually located in a separate facility underless stringent purity conditions than those in which the parametric testis carried out, since wafer fabrication is essentially complete.

[0004] In automated wafer handling during wafer sort, a correlationwafer is used to verify tester setup. The correlation wafer is a controlwafer the functionality of which has been verified and ensures that thetesting system is working properly. After indexing from the cassette tothe prober, the wafers are mounted on a vacuum chuck with Z (vertical)positioning. Using software, mechanical probe needles are aligned andcontacted with bond pads on the wafer to establish electricalcommunication between the testing equipment and the dies on the wafer.The probes are interfaced with the ATE to perform the range of ACfunctional tests based on test algorithms. The type, number and order oftests are defined by the test program.

[0005] After testing, die found to be defective are labeled in acomputer database to exclude the die from subsequent packaging steps.The labeling method is typically performed by placing a drop of ink oneach unacceptable die. Because the ink marking process can be messy andintroduce possible contaminants onto the chip, electronic wafer maps areincreasingly being used to create a computer image of chip location andtest results to categorize good and bad die on the wafer. At the chipassembly stations, the electronic wafer maps are downloaded into anequipment database to ensure that defective chips will not be packaged.

[0006] Typically, the die on a wafer are inked by operation of an inkinghead the position of which over the wafer is automatically controlledusing a software-actuated controller. In the inking of multiple dies atseparate locations on the wafer, the ink head must be moved betweenmultiple positions on the wafer by operation of the software-controlledcontroller. However, this procedure is time-consuming and inefficient.An apparatus is therefore needed which facilitates manualmulti-positioning capability of the ink head over the wafer for inkingmultiple, disparately-spaced die on the wafer.

SUMMARY OF THE INVENTION

[0007] An object of the present invention is to provide an inkingapparatus which has multi-positioning capability in the inking ofdefective dies on a semiconductor wafer.

[0008] Another object of the present invention is to provide an inkingapparatus which may be manually-operated.

[0009] Still another object of the present invention is to provide aninking apparatus which reduces the amount of time required for inkingmultiple dies on a semiconductor wafer.

[0010] Yet another object of the present invention is to provide anapparatus which facilitates quick and yet accurate adjustment of aninking probe in the inking of defective dies on a semiconductor wafer.

[0011] A still further object of the present invention is to provide anapparatus having an inking head which can be adjusted in the X, Y and Zdirections as needed in inking multiple, disparately-located, defectivedies on a semiconductor wafer.

[0012] In accordance with these and other objects and advantages, thepresent invention comprises an inking apparatus including an inking headwhich is manually adjustable in the X, Y and Z directions to facilitatequick and easy positioning of an inking probe in proximity to adefective die on a semiconductor wafer to ink and mark the die forexclusion from further processing. A horizontal positioning plate ishorizontally adjustably mounted on a base plate, and an angularadjustment arm is angularly adjustably mounted on the horizontalpositioning plate. The inking head is vertically adjustably mounted onthe end of the angular adjustment arm and carries an ink reservoir fromwhich ink is dispensed through an inking probe to the dies on the wafer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The invention will now be described, by way of example, withreference to the accompanying drawings, in which:

[0014]FIG. 1 is a perspective view of an illustrative embodiment of thepresent invention;

[0015]FIG. 2 is a top view of the horizontal positioning plate andangular adjustment arm (in phantom) elements of the present invention,more particularly illustrating an illustrative technique for adjustablymounting the angular adjustment arm on the horizontal positioning plate;

[0016]FIG. 3 is a side view of the base plate, horizontal positioningplate and angular adjustment arm elements, in section, of the presentinvention, more particularly illustrating a rack and pinion technique asone example of a mechanism for facilitating horizontal adjustment of thehorizontal positioning plate on the base plate;

[0017]FIG. 4 is a side view of the inking head element of the presentinvention, more particularly illustrating a rack and pinion technique asone example of a mechanism for vertically adjustably mounting the inkinghead on the apparatus;

[0018]FIG. 5 is a side view of the apparatus of the present invention,with the inking head element of the apparatus disposed in a raisedposition above a semiconductor wafer preparatory to inking a die or dieson the wafer;

[0019]FIG. 6 is a side view of the apparatus of the present invention,with the inking head shown lowered into contact with the semiconductorwafer in a typical die-inking operation;

[0020]FIG. 7 is a side view of the apparatus of the present invention,with the inking head shown adjusted to a horizontally-forward positionwith respect to the position illustrated in FIG. 6; and

[0021]FIG. 8 is a top view of the apparatus of the present invention,more particularly illustrating multiple alternative positions of theangular adjustment arm in the inking of dies on a semiconductor wafer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Referring initially to FIGS. 1-4 and 8 of the drawings, anillustrative embodiment of the inking apparatus of the present inventionis generally indicated by reference numeral 1. The inking apparatus 1includes a base plate 2, on which is slidably mounted an elongatedhorizontal positioning plate 3 by techniques known by those skilled inthe art. A horizontal positioning knob 4 includes a knob shaft 5 whichextends through a horizontal shaft opening (not illustrated) provided inthe side of the base plate 2. As illustrated in FIG. 3, a pinion 6fitted with multiple pinion teeth 7 is mounted on the knob shaft 5, andthe pinion teeth 7 mesh with the multiple rack teeth 9 of a horizontalpositioning rack 8 provided on the bottom surface of the horizontalpositioning plate 3. Accordingly, as further illustrated in FIG. 3, thehorizontal positioning plate 3 is mounted for bidirectional horizontalsliding movement on the underlying base plate 2 as the horizontalpositioning knob 4 is rotated in the clockwise or counterclockwisedirection to progressively mesh the pinion teeth 7 with the rack teeth9. In a typical embodiment, the horizontal positioning rack 8 may be4000 mm in length to facilitate a 4000 mm extension of the horizontalpositioning plate 3 with respect to the base plate 2.

[0023] As further illustrated in FIG. 1, an elongated angular adjustmentarm 20 is pivotally mounted on the upper surface of the horizontalpositioning plate 3 by means of a pivot pin 21. An angular adjustmentknob 16 includes a knob shaft 17 which extends through a shaft opening(not illustrated) provided in the angular adjustment arm 20 and on whichis mounted a pinion 14, as illustrated in FIG. 2. The pinon 14 haspinion teeth 15 which mesh with teeth 13 provided along the edge of acrescent-shaped or semicircular angular adjustment opening 12 extendingthrough the horizontal positioning plate 3. Accordingly, as illustratedin FIG. 8, the angular adjustment arm 20 is capable of being positionedat selected angles “+θ” or “−θ” with respect to a longitudinal axisextending through the angular adjustment arm 20, by rotating the angularadjustment knob 16 in the clockwise or counterclockwise direction,whereupon the pinion teeth 15 of the pinion 14 progressively mesh withthe teeth 13 as the rotating pinion 14 traverses the arcuate edge of theangular adjustment opening 12 in the horizontal positioning plate 3.Typically, the angle “+θ” and the angle “−θ” may have a value up toabout 30 degrees, and the angular adjustment arm 20 can be positioned atany angle “+θ” or “−θ” typically up to about 30 degrees by rotating theangular adjustment knob 16 in the counterclockwise or clockwisedirection, respectively.

[0024] A support arm 22 typically angles downwardly from the extendingend of the angular adjustment arm 20 and is typically welded orotherwise attached to the angular adjustment arm 20. A verticaladjustment bracket 24 terminates the extending end of the support arm22, and a substantially “C”-shaped inking head 32 is friction-fitted inthe vertical adjustment bracket 24, according to the knowledge of thoseskilled in the art. A vertical adjustment knob 25 includes a knob shaft26 which extends horizontally through a shaft opening (not illustrated)provided in the vertical adjustment bracket 24. As illustrated in FIG.4, a pinion 27 having multiple pinion teeth 28 is mounted on the knobshaft 26, and the pinion teeth 28 mesh with rack teeth 30 of a verticaladjustment rack 29 provided along a vertical edge of the inking head 32.Accordingly, up or down sliding vertical adjustment of the inking head32 through the vertical adjustment bracket 24 is facilitated byclockwise or counterclockwise rotation, respectively, of the verticaladjustment knob 25, thereby causing the pinion teeth 28 to progressivelymesh with the rack teeth 30 on the vertical adjustment rack 29.

[0025] The inking head 32 includes a horizontal support plate 33 whichsupports an ink reservoir 35, which may be a bottle or other containerthat holds a supply of ink for inking defective dies 41 on asemiconductor wafer 40, as illustrated in FIG. 8 and hereinafter furtherdescribed. An inking probe 36 which communicates with the ink reservoir35 extends downwardly through the support plate 33 for dispensing theink from the ink reservoir 35 to the dies 41. Controller wiring 38extends from a controller (not shown) and may be connected to atransducer 39 which is operably connected to the ink reservoir 35 fordispensing ink from the reservoir 35 onto the defective die or dies 41through the inking probe 36.

[0026] It is understood that any system known by those skilled in theart may be used in conjunction with the inking head 32 to dispense theink from the ink reservoir 35. Accordingly, the controller (notillustrated), controller wiring 38, transducer 39, ink reservoir 35 andinking probe 36, as well as the components used to operably connect thetransducer 39 to the ink reservoir 35 for the dispensing of ink from theink reservoir 35 through the inking probe 36, may be conventional, withone novel aspect of the present invention being the facility formanually adjusting the inking head 32 in vertical relationship withrespect to the semiconductor wafer 40. It is further understood thatvarious mechanisms known by those skilled in the art, other than therack-and-pinion arrangements heretofore described, may be used to effecthorizontal adjustment of the horizontal adjusting plate 3 on the baseplate 2; angular adjustment of the angular adjustment arm 20 withrespect to the horizontal positioning plate 3; and vertical adjustmentof the inking head 32 on the vertical adjustment bracket 24.

[0027] Referring next to FIGS. 5-8, in typical application the inkingapparatus 1 of the present invention is positioned on a supportingsurface 44 typically adjacent to a wafer chuck or other wafer support 42at an inking station in a semiconductor manufacturing facility. Asemiconductor wafer 40, having had multiple dies 41 previouslyfabricated and tested thereon, is positioned on the wafer support 42 formarking of defective dies 41 thereon by operation of the inkingapparatus 1. Accordingly, the inking head 32 of the apparatus 1 ispositioned above the appropriate defective die 41 by operating thehorizontal positioning knob 4 and the angular adjustment knob 16. Thehorizontal positioning knob 4 is rotated in the clockwise direction toadvance the inking head 32 over the wafer 40, such as to the positionillustrated in FIG. 7, or rotated in the counterclockwise direction toretract the inking head 32 back toward the edge of the wafer 40, such asto the position illustrated in FIG. 5. The angular adjustment knob 16 isrotated in the counterclockwise direction to move the angular adjustmentarm 20 and thus, the attached inking head 32, laterally and define aselected angle “+θ” with respect to the longitudinal axis of the angularadjustment arm 20, as illustrated in FIG. 8. Conversely, the angularadjustment knob 16 is rotated in the clockwise direction to move theangular adjustment arm 20 and attached inking head 32 to define aselected angle “−θ” with respect to the longitudinal axis of the angularadjustment arm 20. After the horizontal adjustment knob 4 and theangular adjustment knob 16 are rotated as appropriate to locate theinking head 32 above the appropriate defective die 41 on the wafer 40,the vertical adjustment knob 25 is rotated to lower the inking head 32through the vertical adjustment bracket 24 and thus, facilitate contactof the inking probe 36 with the die 41. Next, the inking controller (notillustrated) is operated to dispense ink from the ink reservoir 35through the inking probe 36 and onto the die 41 to mark or label the die41 as defective. After each of the defective dies 41 is inked, theinking head 32 is first raised on the vertical adjustment bracket 24 bycounterclockwise rotation of the vertical adjustment knob 25 and movedto other locations on the wafer 40 to mark additional defective dies 41thereon. This is accomplished by manual manipulation of the horizontalpositioning knob 4 and the angular adjustment knob 16 in the clockwiseor counterclockwise direction in the manner therefore described.

[0028] While the preferred embodiments of the invention have beendescribed above, it will be recognized and understood that variousmodifications can be made in the invention and the appended claims areintended to cover all such modifications which may fall within thespirit and scope of the invention. It will be appreciated by thoseskilled in the art that the horizontal positioning knob 4 and angularadjustment knob 16 are effective in quickly and precisely positioningthe inking head 32 at a defective die 41 located at any position on thewafer 40.

What is claimed is:
 1. An inking apparatus comprising: a base plate; a horizontal positioning plate horizontally adjustably carried by said base plate; and an inking head carried by said horizontal positioning plate.
 2. The inking apparatus of claim 1 further comprising a horizontal positioning knob operably engaging said horizontal positioning plate for horizontally adjusting said horizontal positioning plate on said base plate.
 3. The inking apparatus of claim 1 further comprising an angular adjustment arm pivotally carried by said horizontal positioning plate for lateral adjustment with respect to said horizontal positioning plate, and wherein said inking head is provided on said angular adjustment arm.
 4. The inking apparatus of claim 3 further comprising a horizontal positioning knob operably engaging said horizontal positioning plate for horizontally adjusting said horizontal positioning plate on said base plate.
 5. The inking apparatus of claim 3 further comprising an angular adjustment knob operably engaging said angular adjustment arm for laterally adjusting said angular adjustment arm with respect to said horizontal positioning plate.
 6. The apparatus of claim 5 further comprising a horizontal positioning knob operably engaging said horizontal positioning plate for horizontally adjusting said horizontal positioning plate on said base plate.
 7. The apparatus of claim 1 further comprising a vertical adjustment bracket carried by said horizontal positioning plate and wherein said inking head is vertically adjustably mounted in said vertical adjustment bracket.
 8. The apparatus of claim 7 further comprising a horizontal positioning knob operably engaging said horizontal positioning plate for horizontally adjusting said horizontal positioning plate on said base plate.
 9. The inking apparatus of claim 7 further comprising an angular adjustment arm pivotally carried by said horizontal positioning plate for lateral adjustment with respect to said horizontal positioning plate and wherein said vertical adjustment bracket is provided on said angular adjustment arm.
 10. The inking apparatus of claim 9 further comprising a horizontal positioning knob operably engaging said horizontal positioning plate for horizontally adjusting said horizontal positioning plate on said base plate.
 10. The inking apparatus of claim 9 further comprising an angular adjustment knob operably engaging said angular adjustment arm for laterally adjusting said angular adjustment arm with respect to said horizontal positioning plate.
 11. The apparatus of claim 10 further comprising a horizontal positioning knob operably engaging said horizontal positioning plate for horizontally adjusting said horizontal positioning plate on said base plate.
 12. An inking apparatus comprising: a base plate; a horizontal positioning plate horizontally adjustably carried by said base plate; and an inking head vertically adjustably carried by said horizontal positioning plate.
 13. The inking apparatus of claim 12 further comprising a horizontal positioning knob operably engaging said horizontal positioning plate for horizontally adjusting said horizontal positioning plate on said base plate.
 14. The inking apparatus of claim 12 further comprising an angular adjustment arm pivotally carried by said horizontal positioning plate for lateral adjustment with respect to said horizontal positioning plate and wherein said inking head is provided on said angular adjustment arm.
 15. The inking apparatus of claim 12 further comprising a vertical adjustment bracket carried by said horizontal positioning plate and wherein said inking head is vertically adjustably mounted in said vertical adjustment bracket, and further comprising a vertical adjustment knob operably engaging said inking head for vertically adjusting said inking head in said vertical adjustment bracket.
 16. An inking apparatus comprising: a base plate; a horizontal positioning plate horizontally adjustably carried by said base plate; an angular adjustment arm pivotally carried by said horizontal positioning plate, said angular adjustment arm laterally adjustable with respect to said horizontal positioning plate; a support arm carried by said angular adjustment arm; a vertical adjustment bracket carried by said support arm; and an inking head vertically adjustably carried by said vertical adjustment bracket.
 17. The inking apparatus of claim 16 further comprising a horizontal positioning knob operably engaging said horizontal positioning plate for horizontally adjusting said horizontal positioning plate on said base plate.
 18. The inking apparatus of claim 16 further comprising an angular adjustment knob operably engaging said angular adjustment arm for laterally adjusting said angular adjustment arm with respect to said horizontal positioning plate.
 19. The inking apparatus of claim 16 further comprising a vertical adjustment knob operably engaging said inking head for vertically adjusting said inking head in said vertical adjustment bracket. 